1. Field of the Invention
The present invention obtains reference vectors representing physical quantities and corrects a correction vector using correction data of the reference vectors. More particularly, the present invention relates to a physical quantity interpolating method of interpolating a color signal in a color space on the basis of the ratio of vector products in coordinates and linear interpolation using amplitudes and angles of the reference vectors, thereby correcting an arbitrary color signal, and a color signal processing circuit and a camera system using the same.
2. Description of the Related Art
Generally, a color image device is equipped with a color conversion circuit for converting the color of an image signal in accordance with input characteristics inherent in the color image device so that satisfactory color reproducibility can be added to pixel signals. A digital camera or the like generally has a matrix circuit or a lookup table circuit for converting a primary or complementary color signal into luminance (Y) and chromatic difference (UV, i.e., R-Y and B-Y) signals. After the signal is converted into the luminance and chromatic difference signals, color adjustment is performed in R-Y and B-Y coordinates.
However, the adjustment performed in this coordinate system is such that, since the signals are input in R-Y and B-Y rectangular coordinates, although individual adjustment can be performed in first to fourth quadrants defined by the R-Y and B-Y axes, it is difficult to freely divide the coordinate system according to hue (angle in polar coordinates) and perform adjustment individually in divided sections.
In such an image adjustment apparatus, in order to improve the color reproducibility from a captured color image input thereto, an adjustment circuit that divides the coordinate system into plural sections according to highly definite hue can be realized by, as implemented in Japanese Unexamined Patent Application Publication No. 2004-274742, having a mechanism for performing a rectangular to polar conversion of chromatic difference signals (R-Y and B-Y) to give luminance, saturation, and hue components and having, after color correction is performed, a mechanism for converting the saturation/hue components back to the chromatic difference signals.